Enteric Methane Emissions and Mitigation Opportunities for Canadian Cattle Production Systems. otherareas/pdf/CcbMethaneemmissionsWittenburg.pdf> (accessed

Methane (CH4) is a colorless, odorless gas generated as a by-product of microbial fermentation of feed in the gastrointestinal tract of ruminant animals. Methane producing bacteria, commonly referred to as methanogens, use the hydrogen and carbon dioxide produced as end products of microbial digestion to generate energy for growth, with CH4 as an end product. Canadian estimates for enteric CH4 emissions from ruminant animals show a 10.6 % increase from 1990 to 2000; 15,994 vs 17,696 kt carbon dioxide (CO2) equivalents/yr respectively. As 1 g CH4 is equivalent to 55.2 kJ of lost feed energy, mitigation strategies can result in improved feed utilization as well as contribute to Canada’s commitment to reduce GHG emissions. Data collected from Canadian research indicate that energy losses associated with enteric CH4 emissions range from 2 to 11.3 % of gross energy intake. Numerous mitigation strategies have been suggested in the literature, including: manipulation of rumen microfloral populations, diet manipulation to provide alternate hydrogen acceptors, diet manipulation to shift the fermentation pathway, management for improved productivity, and genetic selection for low methane emitting animals. Results from Canadian trials show that there are opportunities to reduce enteric methane emissions in commercial production systems. Many of these mitigation strategies will influence carbon sequestration opportunities an